Multihull Structure Thoughts

Discussion in 'Multihulls' started by oldmulti, May 27, 2019.

  1. oldmulti
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    oldmulti Senior Member

    Banque Populaire XI is the latest development of Ultim racing trimarans. The tri is 105 x 75.5 foot with a displacement of 33,000 lbs. The rotating carbon wing mast is 115 foot high and carries 3,770 square foot upwind and 6,460 square foot downwind. Most headsails are on roller furlers as some of the headsails even with lighter fabrics are heavy. The draft is 16.5 foot with all foils down. Banque Populaire XI was launched in April 2021 after 150,000 hours of design and construction.

    The design was done by VPLP Design. The main hull is of a new design by VPLP. It’s flat bottomed, with very fine forward sections, then becomes very deep further aft, where there’s also plenty of flare in the topsides, which increases the beam at deck level. The central hull was designed to move the centre of buoyancy further forward and, with tauter, flatter lines, to optimize her performance at high speeds The floats came from the same moulds as Banque Populaire IX. A state of the art simulator bought from Emirates Team New Zealand enabled the team to spend more than a year trialling numerous different parameters. A lot of work was done on her aerodynamics, with particular attention paid to streamlining the platform around the after beam, the sheet traveller bar and the stern of the central hull. The team also studied the end plate effect of the sail plan on the cockpit fairing, which was extended to the forward beam.

    The major change in the design of Banque Populaire XI is in the foils and control mechanisms. The general balance of the boat was made more flight-friendly, with the distance between the centre of gravity and the hydrodynamic surfaces (i.e. the foils) reduced so that the boat would be much more stable above the water. For the same purpose, weight and the sail plan were moved forward as far as possible so the rudder winglets could function as preventers rather than lifting surfaces. This tri has 2 main lifting foils and 4 “assistance” foils for control purposes depending on the course chosen.

    The builder was CDK Technologies with construction of the central hull and amas was subcontracted to Multiplast in Vannes and Fibre Mechanics in Lymington. The tri structure is carbon fibre, foam, nomex and epoxy. The foils are carbon fibre epoxy. From experience gained on Banque Populaire IX (which was wrecked after hitting a UFO) they have improved the boat's ability to withstand an impact with a UFO. The design team has put in place a sort of "bumper" on the bow arm, which is designed to withstand a shock. This fuse will allow us to preserve the structure of the arm in the event of an impact. Also, fibre optics have been installed at all the hot spots on the boat. With the constant whistling of the foils, you can't always hear what's banging. “We can't be listening to all the boat's noises, and this fibre should enable us to alert us to any possible fragility in the structure.”

    Result of all this design and build? Banque Populaire XI has shown tremendous promise, exceeding 40 knots on each of the first four days of sea trials. “Even we are amazed – compared to its predecessor the boat achieves significant speeds more quickly and with less wind,” says le Cléac’h the skipper. The maximum speed anticipated is 45 knots as the foils start cavitating at 50 knots. The tri has already averaged 35 nots for hours at a time.

    A lot more can be said but the jpegs give the idea. The last jpeg is of Banque Populaire IX, the previous tri that sunk.
     

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  2. oldmulti
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    oldmulti Senior Member

    The Lidgard designed Lidgard 42 (43) is a bridge deck performance cruising catamaran that is intended for serious cruising. The cat is 42.5 x 25.6 foot with a weight of 16,500 lbs. Payload capacity is about 3,500 lbs for a displacement of 20,000 lbs. The 57 foot aluminium mast with a fractional rig has a sail area of mainsail is 807 square foot and the self tacking roller furling jib is 307 square foot. The length to beam is 11.5 to 1. The draft is from 3.8 foot to 7 foot over the daggerboards. You can have optional fixed low aspect ratio keels. The underwing clearance is 3 foot.

    The accommodation is 1 double berth cabin and a large bathroom in one hull and 2 double berth cabins and the galley in the other hull. The main cabin has a large seating area, entertainment area and navigation station. The cockpit is accessed through large glass doors.

    The Lidgard 42 and 43 are basically an extension of the Lidgard 39 performance cruising catamaran which was the basis of the Fusion 40 kit catamaran. The hull shapes on all these vessels are based on the same hull with slight variations on the cats overall beams. This allows the structural design to be very similar in all the designs.

    Construction for these designs is from vinylester or epoxy, e-glass triaxial and biaxial stitched glass with PVC foam cored composites for both shells and internals. Full size DWG files are supplied for both Hull Frames and Deck shell building plus full size plot files for all appendages. The designs are intended for home builders (except for the Fusion 40 which is a kit for the home builder) and have a male mold frame plan available to speed the building of the hull and underwing structures. These cats are relatively light and need to be built to plan well. Vacuum bagging is minimum with infusion for bulkheads and other flat panels. Several of the 39 and 42/43 foot versions have been built. There have been over 60 Fusion 40 kits sold to amateurs and professionals.

    Performance of Lidgard cats in the 40 foot range are considered good with several winning local races in Australia on handicap. Peak speeds of 20 knots have been seen with 8 to 10 knot averages possible in the right conditions. The Bruce Number is about 1.2 depending on the sail options used.

    The jpegs give the idea. A good fast cruiser.
     

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  3. oldmulti
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    oldmulti Senior Member

    The Overboat 100C and 100F are designed by Vincent Dufour and his team at Néocéan. The Overboat 100C and 100F are electric powered 1 person cats for fun. The one person Overboat 100C is 10.2 x 4.5 foot with an overall length over motor of 11 foot. The non foiling, displacement cat weights to 242 lbs with a displacement of 462 lbs. The draft is 0.9 foot. The electric motor is 4.5 kW, 50 volts batteries of 5.7 kWh. Fast recharge time: 1 hr 45 minutes. The top speed is 12 knots, a cruising speed of 8 knots and a range of 16 miles or 2 hours running time at cruising speed.

    The one person Overboat 100F is 10.2 x 4.5 foot with an overall length over motor of 11 foot. The width over the foils is 5.6 foot. The foiling cat weights to 286 lbs with a displacement of 577 lbs. The draft is 0.9 foot over the hull, 2.9 foot over the foils. There are 3 self adjusting T foils. The forward foil lifting area is 2 x 880 cm². The aft foil lifting area is 1200 cm². Propulsion Electrique 48 V Power P 4.5 kW, 50 volts batteries of 5.7 kWh. Fast recharge time: 1 hr 45 minutes. The top speed is 15 knots, a cruising speed of 12 knots, a take-off speed of 8 knots and a range of 24 miles or 2 hours running time at cruising speed. Notice the 50% cruising speed increase using the foils on the same boat using the same engine and batteries.

    The really interesting part of this craft is the foils are fully self-adjusting. Thanks to a self-regulating system, the boat rises on its carbon foils as soon as it reaches a speed of 8 knots. The flight height is preset before the launch, from 10 cm - for shallow areas - to 0.70 cm - the maximum height and preset for our test. The foils are regulated 100 times per second thanks to the control electronics integrated in the boat. The ascent is done in two steps - a first level at 8 knots before taking its maximum height.

    The hulls are polyester / fiberglass. No need for foam in this size. The foils are carbon fibre.

    The tests of the 100F foiling version claim the cat does not require any formal training to drive. Read the manual follow the instructions to preset things jump on board and drive. The steering is very sensitive so you have to be smooth in your movements. The foiler can drive through 1.5 foot seas without problems but is not a big sea vessel.

    The jpegs give the idea. A very interesting boat.
     

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  4. oldmulti
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    oldmulti Senior Member

    The Overboat 150F are designed by Vincent Dufour and his team at Néocéan. The Overboat 150F are electric powered 2 person cats for fun. The 2 person Overboat 150F is 11 x 4.7 foot with an overall length over motor of 11.9 foot. The foiling cat weights to 397 lbs with a displacement of 727 lbs. The draft is 0.9 foot over the hull, 2.9 foot over the foils. There are 3 self adjusting T foils. The forward foil lifting area is 2 x 880 cm². The aft foil lifting area is 1200 cm². The electric motor is 10 kW 50 volt, 50 volt batteries of 10 kWh. Fast recharge time: 1 hr 45 minutes. The top speed is 20 knots, a cruising speed of 15 knots and a range of 30 miles or 2 hours running time at cruising speed.

    Again, the really interesting part of this craft is the foils are fully self-adjusting. Thanks to a self-regulating system, the boat rises on its carbon foils as soon as it reaches a speed of 10 knots. The flight height is preset before the launch, from 10 cm - for shallow areas - to 0.70 cm - the maximum height and preset for the test. The foils are regulated 100 times per second thanks to the control electronics integrated in the boat. The ascent is done in two steps - a first level at 10 knots before taking its maximum height. The 150F, 2 seater is equipped with the latest generation of hydrofoils that stabilizes automatically with patented pitch regulation technology that provides cruising stability and control It even has a reverse gear, to facilitate maneuvers. The two front foils are easily raised, as well as the base for the engine and the rear support plane, for sailing in shallow waters. These features makes the boat fun and easy to handle and can be driven by someone with minimum training. As this is a faster craft with passenger capability it is recommended that a person learns how to fully handle the vessel.

    The hulls are polyester / fiberglass. No need for foam in this size. The foils are carbon fibre.

    The jpegs give the idea. Finally, the company is also working on a 7.50 m (25 foot) catamaran with a 40 kW motor for a top speed of 30 knots. The PDF gives a diagram of the craft.
     

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  5. oldmulti
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    oldmulti Senior Member

    Boutique boat builder Soyaslan has launched what is "believed" to be the world’s longest cold-moulded catamaran, the Cat63. It was designed and built by the specialist Turkish builder, with styling from Tumer Design Studio. The CAT63 measures 63.6 foot long. On its fixed aluminium mast, it carries a 1076 square foot mainsail, 516 square foot self tacking jib and a 1560 square foot gennaker. It is powered by twin Yanmar 110 HP engines, hooked up to big ZF saildrives, for an 8.5 knot cruising speed and over 10 knots full throttle. There are 60 kWh of lithium batteries aboard and eight 430 Watt solar panels. The are low aspect ratio keels with swinging centreboards inside to allow greater draft.

    Sorry about the lack of numbers but when I found the first jpeg below it became clear why they may not want to mention some numbers. The Soyaslan boat yard has built many impressive, large power and monohull yachts. They have built in wood, fiberglass, steel etc and have superb interior fittings and layouts. When I looked at the first jpeg I saw a cat that had (from here guesses) about 8 to 1 length to beam (or worse) length to beam ratio hulls, a very low underwing clearance, a wing deck with high internal headroom and luxury internal fit outs. To have beds and walking space across a hull, mean the hulls have to be at least 8 foot wide on a 63 foot waterline. Nothing wrong with fat hulls, but when you load them down with a luxury interior, big engines, solar systems etc and it effects your underwing clearance, then you start to have issues. The top speed of the cat under power also gives another hint of what may be a high displacement figure. Cats this length and with this power, but lighter in build can do more than 10 knots under power. If space is what the owner requested, OK.

    The jpegs give an idea of the accommodation. The below deck layout provides space for eight passengers, located in two double and two twin cabins, and cabin space for three crew members (in berths). The interiors are large and bright, according to a clear colour palette, with touches of blue and orange, the colours of the yard. The flybridge is large and comfortable allowing the helmsperson good vision and access to sail controls. There is also a full navigation station in the saloon below. The cockpit is large and at the stern, an electrically lowerable platform functions as a small beach and at the same time as a shelter for a 3.5 meter tender.

    This is a complex design built using the cold-moulded construction. The quality of the structure is a testament to the skills of the Soyaslan’s workers and designers. “We have good experience in engineering and manufacturing with this method,” said Founder of the company, Can Soyaslan. “We have engineered and built cold-moulded yachts which are already 30-plus years old. To date, we have produced more than 100 boats and yachts.” Cold moulding is the method of building up a shape by forming sheets or planks of wood over a plug or frame. The individual wooden elements are glued together with high-performance epoxy and later sheathed in epoxy for protection and longevity. “In the final look, users cannot tell the difference between a cold-moulded yacht and a GRP or metal one,” continued Soyaslan. “In practice, the durability and longevity of the hull is without comparison. Wooden yachts can last well over a hundred years, while the vibration, sound and heat insulation are much better. Weight for weight, there is little difference between cold-moulding and GRP."

    My comment is it depends on what type of GRP. Solid glass, yes cold moulded would compete or be lighter. Carbon foam glass in this size range would be lighter than cold moulded construction. The very few jpegs (youtubes) I saw of the structure indicate a solidly built cat.

    Little was said about the Cat63 performance beyond: “with a generous sailplan … the boat achieved better than 10 knots during sea trials. A stylish bowsprit offers plenty of downwind sailing options.”

    Look at the jpegs, it will give an idea of the Cat63 design and intended purpose. This is a “luxury” cruiser not a racer. I just worry about the underwing clearance for anything more than close to shore work.
     

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    Last edited: Sep 3, 2022
  6. oldmulti
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    oldmulti Senior Member

    Marsaudon Composites’ and The Lombard design office have gotten together to produce a larger version of the TS 42 and 50. Under the name of ORC (Ocean Rider Catamarans) the ORC 57 is 60.3 x 29.5 foot with a weight of 25,310 lbs and a displacement of 31,200 lbs. The Sparcraft aluminium fixed mast, anodized in grey has one-level spreaders for the double 1x19 stainless-steel diamond cables. One Dyneema® Ø 20 mm forestay, one pair of 19 mm 1x19 stainless-steel cap shrouds, one pair of 14 mm 1x19 stainless-steel lower shrouds and two pairs of 12/14 mm 1x19 stainless-steel diamond cables. The mast carries a square head mainsail of 1160 square foot, a 938 square foot genoa, a 2140 square foot Gennaker and a 3400 square foot spinnaker. The Length to beam of the hulls is greater than 12 to 1. The underwing clearance is 3.4 foot. The draft over the spade rudders is 5 foot and with daggerboards down 14.7 foot. This is a serious upwind performer. If you wish to improve performance you can order a Lorima Carbon Fibre rotating wing mast. Engines: 2 x Saildrive 57 HP.

    Both the mast and the inclined daggerboards have been moved further aft than on previous models, creating space for a range of different sized headsails and leading to an efficient high aspect-ratio mainsail. This solution allows the cat to remain well-balanced and well-mannered under a wide range of different sail configurations depending on the wind conditions and on whether the boat is being cruised or raced. The hull shape of the ORC 57 is a progression from the earlier models, following the same light displacement principles with fine hull shapes. Lombard drew a new shape for the bows to increase efficiency and reduce the tendency for bow-down trim.

    The base model has four double cabins, an optional “owners’ hull” with double bed aft and large ensuite forward can be added portside. The team is considering a lightweight, low-consumption “air conditioning” option in the cabins and a dedicated skipper/crew cabin with its own en-suite accessed from the deck, as it’s expected that at this size some owners will expect more comfort and more assistance from a professional crew than is the case with smaller models. Washing machines and other appliances can also be specified as options for those with longer distance cruising plans. The main bridgedeck cabin has a galley, seating and inside navigation/helming position. The cockpit is large with helming positions near the outboard sides of the cockpit. Owners of the ORC42 and 50 have found that a large solar panel mounted on the davits generates sufficient energy for all onboard needs in anything but abysmally poor weather, but the 57 has the option of additional roof-mounted solar panels which will likely be needed to power air conditioning if specified.

    Tests have found that “However, with a wind of less than 10 knots, the ORC 57 manages to keep speeds close to the wind. Where most of the cruising catamarans would have had to put the engine on.” And “The ORC 57 exceeded 20 knots”. This ORC 57 can run at wind speed up to about 15 knots and can peak at 30 knots boat speed given the right conditions. The very core of this design is a very high-performance cruiser racer.

    The ORC 57 is built from infused fiberglass/vinylester resin sandwich construction on PVC foam core. Laminated carbon ribbands (flanges) and composite bulkhead structure. All the composite parts are vacuum infused and bonded by contact lamination. Hulls, deck and roof in a white gelcoat finished. Non-slip white gelcoat on the deck, the cockpit floor, the saloon floor and under the nacelle High performance epoxy primer layer applied below the waterline. One carbon mast post + 2 carbon saloon roof posts. Two stainless-steel, black thermo-lacquered cockpit posts. Two composite daggerboards, vinylester/glass, infused, with carbon reinforcements. Two spade composite rudders on stainless-steel rudder stocks with JP3 self-aligning rudder bearings. Two carbon tillers with a white gelcoat finish and connected by two carbon tubes in the aft beam with JP3 track and ball-bearing car system for guidance in the aft beam.

    This is a serious high performance cruising racer catamaran that literally will sail rings around most other cruising cats of the same length. A very well designed and built vessel. The jpegs give the idea.
     

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    Last edited: Sep 4, 2022
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  7. oldmulti
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    oldmulti Senior Member

    Monkey Mia is a remote part of the Western Australia coast famed for its marine life. The small community lives on eco-tourism. There are 2 charter catamarans in town. One is the ex racing 60 foot Shotover catamaran the other is the 57 foot bridge deck cabin, charter catamaran called Aristocat 2. Aristocrat 2 has served for over 20 years doing daily charters before the owners have decided to sell the boat and business.

    Aristocat 2 is 57.6 x 27.9 foot with a weight of 36,000 lbs and a displacement of 44,800 lbs. The 70 foot fixed aluminum mast carries a 1,000 square foot mainsail and a 630 square foot self-tacking jib. There is a removable inner forestay that can carry a 300 square foot smaller jib to form a cutter rig. The length to beam of the hulls is about 10 to 1. The draft is 3.8 foot over low aspect keels. The underwing clearance is 3.5 foot. The engines started out as 2 x 90 HP outboards which provided a peak speed of 16 Knots and a cruise speed of 9 Knots. The engines were replaced in 2022 by 2 x 240 HP Yanmar diesels. Maximum speed now is 18 Knots with a cruising speed of 10 Knots. Fuel capacity is 1600 liters with a fuel consumption of 3 Ltr/mile. The range is 530 miles at 9 Knots with a 10% reserve.

    The accommodation is basically for charter work, there are 4 double berths in the hulls and a toilet area. The main saloon is mainly seating and a bar with domestic fridge. Externally there is a large deck and cockpit area for viewing of the Dugongs, Dolphins, Whale Sharks and sea grass etc. The helming station is raised, well protected and separated from the charter guests.

    The cat is built in aluminum with 5 mm bottom and hull side plates. The underwing, deck and superstructure plating is 4 mm with supporting stringers and a frame spacing of 600 mm.

    Aluminum if well cared for, will last a long time. This cat design could easily be modified to a good capable long term cruiser. The jpegs give the idea. The PDF is a description of the design by Global Marine design.
     

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    Last edited: Sep 4, 2022
  8. Coastal Ogre
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    Coastal Ogre Junior Member

    OM,

    Any musings on longeron designs - or as some NA's prefer to call them: central spars? And the effort v. reward ratio over having a separate bow sprit?

    Contemplating removing my heavy polyester & gelcoat 'catwalk' and adding a CF combined unit (running it under the aluminum crossbeam perhaps like Fountaine Pajot). Primary desire would be for ease of flying a Code 0 or a larger Asym. This would be in lieu of adding a bow sprit alone on my (older, smaller) 38' French Cat and attempting to keep the weight change neutral.

    Something like Outremer, Grainger, Schionning, Gunboat, Kinetic, etc. provide as standard...

    I would not however be incorporating the anchor and chain into the component, as I am going to bring that back to the bridgedeck for weight centralization. Any insight would be appreciated!

    Grazie - Ogre
     
  9. oldmulti
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    oldmulti Senior Member

    Blue Coast Yachts 160 is the latest variation on the super rich market. A combination of Cosle (no internet listing) and McLaren Applied Technologies (the car company) are listed as co designers of the trimaran. The Blue Coast Yachts 160 (or UltraLuxum CXL) is 160 x 57.4 foot and can be folded, by swing arms, to 36 foot wide for mooring. The 160 foot carbon fibre mast carries 3,570 square foot of sail. The minimum draft is 5.7 foot. The engine power is hybrid electric and can provide a 15 knot maximum speed.

    The accommodation is vast spread over the 3 hulls. Each float has 2 large double berth cabins, associated ensuite bathrooms and seating area. The main hull has a very large master cabin, four guest cabins, three crew cabins, a lounge, a dining room, a kitchen, and an optional garage to house your optional McLaren sports car. The main deck above the sleeping cabin deck is a socialising entertainment area is again vast with multiple seating and entertainment areas. The flybridge is above the main deck containing helming and push button controls for sail handling etc. When you get to craft this big, they are as much machines as they are yachts. Sails this large weight over 1000 lbs which require significant crew or automated winches to raise or lower. Headsail tacking loads are measured in tons not lbs.

    The proposed build is claimed to be full carbon fibre epoxy over PVC foam. The swing wing arms would require significant engineering to work continuously.

    These 100 foot plus multihull cruisers are spectacular to look at but all have similar issues. They have so much stability that it does not matter if it is a cat or a tri. A 100 foot plus cruiser does not have much sailing “feel”, they do not respond instantly to steering input etc. These size vessels have a lot of momentum and take time to change direction etc. The largest charter cruising cat I have steered was 84 foot long and had 5 foot draft over the rudders. Down wind the rudders were too small to provide rapid steering responses and you had to anticipate how the cat would move in the seaway when you changed course. Yes, the 84 foot cat could hit 20 knots but it had no “feeling” or responsiveness that you could get in a 30 footer. PS the 84 footer (which had a big rig and good slim hull shape) in most conditions would sail at 10 to 12 knots.

    The jpegs give the idea. Dreams come at a high price and the 5 crew you would need to “help” you sail the tri increases your expenses. Are the joys of impressing the poor of the world.

    Coastal Ogre I will address your question tomorrow.
     

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    Last edited: Sep 5, 2022
  10. oldmulti
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    oldmulti Senior Member

    In simple terms we need to understand what you are trying to achieve Coastal Orge. If it is to fly a Code 0 or an asymmetric from a prodder in front of your forebeam, that is a short aluminium or carbon fibre pole, that acts as a compression item for tension wires that go to the cat bows to handle the majority of the tension loads. You can then build a very light walkway to the bows. Minimum effort and the prodder can be folded back to the forebeam to keep your mooring fees down. The first jpeg (long 8) gives the idea.

    But I suspect you want an integrated walkway and prodder that extends past the forebeam. If the walk way/longeron goes under the forebeam, I am assuming that the dolphin striker would remain in position on the forebeam. Now decisions have to be made. If the longeron is not going to have any supporting wires in front of the forebeam then you are seriously going to have to design the walk way/longeron to carry the loads of the Code 0 and or asymmetric. The following web site will give some guide. Look at Can Anyone Explain the Forces on a Longeron? https://www.boatdesign.net/threads/can-anyone-explain-the-forces-on-a-longeron.63976/

    This thread leads to the basic issue here, a longeron needs to be designed to suit the forces that you propose to load on it. If it’s a fixed length that makes your cat EG 42 foot instead of 38 foot LOA (jpeg long 9) and you have no additional mooring costs it is simpler to design.

    But if you want the prodder component to slide back under the walkway to reduce its mooring length (jpeg long 6) that adds to the design complexity. The Farrier trimaran guys ( main groups.io Group https://fct.groups.io/g/main ) have had long discussions on retractable prodders for various sizes of tri’s. Look at the Farrier tri message board over the last 3 months. Also if you join the Farrier group there are PDF’s of many aspects of Farrier trimarans that may include prodder designs and builds.

    What it required is the prodder must be designed like a mast with about 70 % of the carbon going the length of the tube. The diameter and wall thickness needs to be calculated from the “forestay” load, length of prodder tube from the support point tube and the safety factor you want.

    If you are capable of doing the design work, excellent but do not underestimate the loads you will be dealing with. If you are running an asymmetric spinnaker downwind, it may be loaded because someone has steered upwind to avoid something. In short speak to a designer if you are unsure.

    A few other jpegs may give more options. The Raku 48 side view give an idea of the size a fixed length longeron.

    Hope it works out for you.
     

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  11. oldmulti
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    oldmulti Senior Member

    The Ocean Renegade R5 (and Mk11) out of Cape Town, South Africa, designed by Ocean Renegade Design Office with KND Design for Naval Architecture & Engineering. The 54' carbon re-enforced cat was completed in December of 2020 and uses a Torqeedo Deep Blue propulsion system. The R5 is 54.5 x 26.9 foot with a weight of 24,912 lbs. The aluminium Sparcraft mast is 63.6 foot long (there is an optional carbon fibre mast) that carries a mainsail - Ullman FiberPath (50% carbon / 50% twaron) - 979 square foot, self-tacking Jib - Ullman FibrePath (50% Carbon / 50% twaron) - 452 square foot, storm Jib – Ullman Crosscut Dacron – 140 square foot, Code 0 – Ullman Red line Racing (Radial laminate) - 1076 square foot and an Asymmetrical spinnaker - Blue line Cruising (Radial nylon) – 1926 square foot. The length to beam of the hulls is about 13 to 1. The minimum draft over rudders is 4.9 foot and over the daggerboards of 9.8 foot. The underwing clearance is 3.6 foot. The motive power is two 25kw pod drives and a single 40kwh BMW i3 battery. Auxiliary power is provided by a Fischer Panda AC generator and 8 400 watt solar panels on the cabin roof. There is an option for two Yanmar 57 HP diesels.

    The accommodation has 3 double cabins with ensuite toilets in the hulls. Also, there is a storage area for surf boats dinghies etc aft in one hull. The main saloon has a large galley, seating area with large glass doors leading to an aft cockpit. The helm position is in the main saloon beside the forward sail control cockpit (as in Whites Atlantic cats). This allows immediate access to the mast base and most sail controls. There is an optional ‘sail by wire’ package that takes steering system to another level and adds 2 more outboard seated tiller steering positions, each with remote control of the traveller line driver and trimming winches, creating a full vision one handed sailing experience.

    The construction is vacuum bagged or resin infused foam glass epoxy in the majority of the structure. The bulkheads are carbon fibre foam. The entire shell is fully baked (at 60 degrees Celsius for 20 hours) which strengthens the hulls beyond normal curing. I liked little things like the solid 48 mm Duplex 2205 stainless steel rudder shafts which are stronger than 316 Stainless Steel shafts. The majority of the internal furniture is foam glass with veneers. Most of the furniture is structural.

    The cat’s performance with the above numbers will be good. We are talking about 300 mile days and peaks over 20 knots in the right conditions.

    The jpegs give the idea. This is a very well designed cat and is an excellent fast ocean cruiser. The build team appears to have a lot of experience and the R5 has already done ocean crossings.
     

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  12. bajansailor
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    bajansailor Marine Surveyor

    She does look very fine indeed, with lots of neat ideas.
    That forward cockpit makes a lot of sense really - in nice weather simply leave the doors open, and have the breeze blowing through, and if the weather turns nasty then simply shut the doors (and batten down as required).
    Excellent visibility forward, and still reasonable aft for backing into a berth.

    Re the Ren34 photo, showing a half mould of the hull, that looks like a neat idea having those 'knobs' (for want of a better term) - are there corresponding dimples in the opposite mould? That should help to lock the two halves of the hull together, prior to overlaminations?
     
  13. oldmulti
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    Location: australia

    oldmulti Senior Member

    Banjansailor. The photos I saw of all the mouldings of this boat had registration "knobs" on all the half moulds. These guys appear to have a lot of experience and know the importance of alignment of mouldings to get accurate consistent outcomes. Something that a few Farrier builders don't understand until they try and mate their 2 half hulls together and find that when Ian Farrier said a half bulkhead should be 4611 mm from a point, he means 4611 mm not 4605 or 4615 m.
     
  14. Coastal Ogre
    Joined: Jun 2019
    Posts: 47
    Likes: 9, Points: 8
    Location: Florida

    Coastal Ogre Junior Member

    OM,

    Thank you for this information!


    Final question: how long is too long? I see Grainger maintains a 66% of max beam for the entire structure forward of the bridge deck.

    Regards - Ogre
     

  15. oldmulti
    Joined: May 2019
    Posts: 2,021
    Likes: 1,232, Points: 113
    Location: australia

    oldmulti Senior Member

    Coastal Orge. The following are a few jpegs of a longeron build for about 49 foot cat. The base design is a Schoinning cat. This longeron is a relatively simple “add on” to a new build. The longeron in this case also has an anchoring guide and drop point at the forebeam and also an additional carbon fibre dolphin striker to reinforce to forebeam. A standard dolphin striker will be ok as long as the attachment to the forebeam and forward end of the wing deck is done well.

    The build is done using foam e-glass in epoxy with longitudinal reinforcing at each corner of the triangular build. The anchor take off point both attaches the forebeam and provides the support for the anchor chain rollers etc. The walls of the anchor chain take off are 18 mm solid glass epoxy to handle the side shock loads of the anchor chain/rope as the cat hunts at anchor. The “paddle” at the front of the longeron allows a couple of attachment points fore a EG code Zero and an asymmetric spinnaker.

    The forebeam build jpegs are also attached. This is a “standard” old style forebeam build for a Schoinning of strip plank cedar with glass epoxy either side of the beam skin.

    The jpegs give the idea. Hope this provides some additional clues.
     

    Attached Files:

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